The invention relates to a drilling device for frameless glasses with a drill head, which can be moved up and down.
For frameless glasses, the temples and bridges are fastened directly to the lenses. For this purpose, fine boreholes must be produced in the two edge regions of the lenses. If the glasses are to be seated correctly and have a good appearance, it is necessary to produce the boreholes relatively accurately in the positions, specified by the manufacturer. In this connection, it is especially important to maintain the specified slope of the boreholes and the distance of the boreholes from the edge of the lenses.
Previously, optometrists generally used a normal drill press with a spherical or ball joint-like holding device for the lenses, on which the lenses are disposed intuitively in relation to slope and position, so that the boreholes correspond as accurately as possible to the desired specifications. It is obvious that inaccuracies are unavoidable with this procedure. In any case, this procedure requires much experience and the expenditure of relatively much time.
It is therefore an object of the invention to provide a device of the type named above, which permits boreholes to be produced in frameless glasses within a relatively short time and with a high degree of accuracy.
This objective is accomplished by the inventive drilling device, which is characterized in that the drill head can be inclined to either side and in that a holding device is provided for the two lenses of the glasses, in which the opposite edge regions are accessible to the drill bit of the drill head.
The essential data of the boreholes can be taken over especially from the so-called supporting discs. The latter are simple discs of glass or plastic, which imitate the lenses and are mounted at or in the frame, so that the customer can get an impression of the effect of the glasses, while at the premises of the optician.
To begin with, the supporting discs can be clamped in the inventive holding device and fine pins, drills, which are not required, or the like can be inserted in the boreholes, so that the necessary slope of the boreholes can be recognized. This slope can then be transferred by the optician to the drill bit, which is to be used to produce the boreholes, in that the drill head is appropriately inclined laterally. The optician can then approach the position of the drill holes with the drill bit and move the cross slide subsequently until the drill bit has reached the edge of the respective supporting disc. The slope of the borehole and the distance from the edge can then be transferred by the optician in the course of the further procedure to the actual lenses. The drill head must be shifted from the first lens to the second by the optician merely by inclining the drill head to the other side in mirror image fashion. The same applies for the distance from the edge.
Preferably, the drilling device has a base plate, on which the cross slide is disposed. Moreover, an upright guide for the drill head, which can be swiveled about a horizontal axis, is mounted at the base plate. In this way, the slope of the drill head can be varied. Moreover, the drill head can be moved up and down at the guide in the manner basically customary for drill presses.
Preferably, adjustable stops are provided for the inclination of the guide and of the drill head and are located, for example, at a plate, which rises up in front of the guide. The stops can be formed by pins, which are inserted into the boreholes of a series of boreholes.
Advisably, there is a detachable working plate, which forms the actual holding device for the two lenses, on the cross slide. For clamping the lenses, the holding device can be taken down. After the lenses have been inserted precisely, the whole of the working plate, together with the lenses, can be placed back on the cross slide. In this connection, the lower slide preferably is constructed as a longitudinal slide and the upper slide as a transverse slide, in each case in relation to the position of the optician, who is working with the instrument.
The displacements of the transverse slide can be indicated, for example, on a scale, so that the distance, which the drill bit covers from the edge of a lens to the precise drilling position, can be determined. The corresponding applies to the distances, for example, between two superimposed boreholes. Spindle gearing may be provided for shifting the slides.
The holding device may consist simply of an overlay with a high friction, for example of a soft PVC, which is spanned in the positions of the two lenses by clamping straps. Cushions of a soft material, such as moos rubber, may be provided at the clamping straps and exert pressure on the lenses, pressing these against the support without damaging or destroying the glasses.
The whole of the cross slide can also be inclined in the forwards-backwards direction if, in a particular case, the temples are to be mounted obliquely at the lenses. As a rule, however, the cross slide lies horizontally on the machine table.